Hardee's Mushroom and Swiss Burger Copycat Recipe

This Hardee’s Mushroom and Swiss burger copycat makes two burgers in about 35 minutes: a 150 g (1/3 lb) Angus patty charbroiled to 160°F (71°C), a slice of melted Swiss, a mushroom sauce made from scratch and a toasted bun. It rebuilds the old Mushroom & Swiss Thickburger. A short variant gives the burger Hardee’s sells today, a Quarter Pound patty on a brioche-style bun. I worked from Hardee’s own menu description, checked on November 12, 2026. The quantities are mine.

Home reproduction, not the official recipe. Hardee’s does not publish the recipe, the ingredient list or the allergens of its mushroom sauce. It does not publish the number of Swiss slices, the amount of sauce or the assembly order either. Every weight and step here is my own estimate, built from the official menu description and tested in a home kitchen.

What is on a Hardee’s Mushroom and Swiss?

Hardee’s describes the current US Mushroom & Swiss as a ‘Quarter Pound 100% Angus beef patty topped with melted Swiss and finished with mushroom sauce, all served on a perfectly toasted Brioche style bun’, at 580 calories. That is the wording on hardees.com, checked on November 12, 2026. The Double Mushroom & Swiss swaps in two Quarter Pound patties and comes to 860 calories, according to its official page.

Four parts. No lettuce, no ketchup, no mustard. With so little else on the bun, the burger lives or dies on the patty and the sauce. The official page gives no price, no ingredient list and no allergens, and the nutrition guide it points to is published as an image only.

Mushroom & Swiss Thickburger vs the current Mushroom & Swiss

The Mushroom & Swiss Thickburger used a 1/3 lb patty, while the burger Hardee’s sells today uses a Quarter Pound patty and no longer carries the Thickburger name. On November 12, 2026, the US menu files the Mushroom & Swiss under ‘Charbroiled Burgers’. The word Thickburger is gone.

Hardee’s launched the Thickburger line in 2003. By 2008 it had three sizes: the Little Thickburger at 1/4 lb, the Original at 1/3 lb and the Monster at 2/3 lb, according to Nation’s Restaurant News. In June 2024, Mashed reported that Hardee’s had ‘killed off Thick Burgers’ and brought its biggest patties down to a quarter pound (Mashed via Yahoo). I could not find an official date for the name change, the smaller patty or the switch to a brioche-style bun.

Bar chart of beef per Hardee’s burger: Little Thickburger 1/4 lb (113 g), Original Thickburger 1/3 lb (151 g), Monster Thickburger 2/3 lb (302 g) in 2008; Mushroom & Swiss Quarter Pound (113 g) and Double (227 g) in 2026; this copycat 150 g (5.3 oz). Sources: Nation’s Restaurant News 2008, hardees.com checked Nov. 12, 2026. (Chart: Burger Breton, CC BY 4.0, data from Nation’s Restaurant News (2008) and hardees.com (checked 2026-11-12), rendered with QuickChart; render locally as SVG/WebP 800x450, loading lazy)

Mushroom & Swiss Thickburger vs today’s Mushroom & Swiss vs this copycat: 1/3 lb patty, then a Quarter Pound 100% Angus patty, then 150 g (5.3 oz) or 113 g (4 oz). Charbroiled, melted Swiss, mushroom sauce, toasted brioche-style bun; 580 calories for the single and 860 for the double (hardees.com, checked Nov. 12, 2026). (Table: Burger Breton, CC BY 4.0, data from hardees.com (Mushroom & Swiss and Double Mushroom & Swiss pages, checked 2026-11-12) and Nation’s Restaurant News (2008))

I lead with the 1/3 lb version, and given the choice I’d make it over today’s burger every time. A quarter pound of beef ends up thin under a quarter cup of sauce. A third of a pound holds its own. It also matches the 150 g patty of our Hardee’s Monster Thickburger copycat, from the same Thickburger line.

Ingredients for 2 Mushroom & Swiss Thickburgers

You need 300 g of ground Angus beef, two slices of Swiss, two buns and a short list of pantry items for the sauce.

Burgers

• 300 g (10.6 oz) ground Angus beef, 80/20, divided into two 150 g (5.3 oz) patties
• 2 slices Swiss cheese, about 20 g (0.7 oz) each
• 2 burger buns (sesame or plain; brioche-style for the current version)
• 1 tbsp (14 g) softened butter, for the buns
• Kosher salt and freshly ground black pepper

Mushroom sauce (about 1/2 cup, 120 ml)

• 2 tbsp (28 g) unsalted butter
• 150 g (5.3 oz) white button mushrooms, thinly sliced
• 1 tbsp (8 g) all-purpose flour
• 1/2 cup (120 ml) beef broth
• 1 tsp Worcestershire sauce
• 1/4 tsp onion powder
• Salt and black pepper to taste

Hardee’s mushroom sauce recipe

A Hardee’s-style mushroom sauce is sliced mushrooms browned in butter, then thickened with a little flour and simmered in beef broth with Worcestershire until it coats a spoon. Hardee’s has never published its own recipe. An ingredient list circulates online, but I could not date it or trace it to the chain, so I left it out.

I skip canned soup on purpose. The most visible copycat, on Food.com, uses a 10.5 oz can of Campbell’s Golden Mushroom soup, a 4.5 oz can of sliced mushrooms, Worcestershire, Accent (MSG) and Lawry’s seasoned salt. Its own reviewers ask for more Worcestershire, butter and fresh mushrooms. My scratch version starts from exactly that. Fresh mushrooms browned hard in butter give the sauce a roasted edge that canned ones never get, and the broth and flour turn it glossy in four minutes.

Purists can still go the soup route: warm half a can of Golden Mushroom soup with your browned fresh mushrooms and a teaspoon of Worcestershire. It is faster, saltier and closer to the old-school copycats.

Step by step: how to make the copycat

Shape and chill the patties, make the sauce, charbroil the beef to 160°F (71°C), melt the Swiss, toast the buns and assemble.

1. Shape the patties

Divide the beef into two 150 g (5.3 oz) balls and press each into a patty about 1 cm (1/2 in) wider than the bun, with a shallow dimple in the center. Chill them for 15 minutes so they hold together on the grates.

2. Make the mushroom sauce

Melt the butter in a skillet over medium-high heat and cook the mushrooms for 5 to 6 minutes, without stirring for the first 2, until browned. Don’t reach for the spoon early: stirred straight away, the mushrooms give up their water and turn grey instead of brown. Sprinkle in the flour, stir for 1 minute, then add the broth, Worcestershire and onion powder and simmer for 3 to 4 minutes until thick enough to coat a spoon. Season with salt and pepper and keep warm on low.

Sliced cremini (baby bella) mushrooms browned in butter and oil over medium heat, the first step of the Hardee’s-style mushroom sauce: let them sit undisturbed for 2 minutes so they color before adding the flour and beef broth. Button mushrooms brown the same way. (Photo: Cheryl from River City (Richmond), VA, USA, CC BY-SA 2.0, https://commons.wikimedia.org/wiki/File:Saut%C3%A9ed\_baby\_bella\_(portobello)\_mushrooms.jpg (640x480, loading lazy))

3. Heat the grill

Heat a gas or charcoal grill, or a cast-iron grill pan, over high heat, around 450 to 500°F (230 to 260°C). Oil the grates lightly so the patties release cleanly.

4. Season and charbroil the patties

Salt and pepper both sides of the patties just before cooking, then grill them for about 4 minutes per side, without pressing, until an instant-read thermometer shows 160°F (71°C) in the center. A 113 g (4 oz) patty for the Quarter Pound variant needs about 3 minutes per side.

5. Melt the Swiss

Lay a slice of Swiss on each patty during the last minute of cooking and cover with a lid or a metal bowl until it melts and drapes over the edges.

6. Toast the buns

Butter the cut sides of the buns and toast them, cut side down, for 30 to 60 seconds on the grill or in a dry skillet until golden.

7. Assemble the burgers

Place each cheese-topped patty on a bottom bun, spoon 50 to 60 ml (about 1/4 cup) of mushroom sauce over the Swiss, and close with the top bun. Serve right away, while the sauce is hot and the cheese is soft.

A thick, glossy mushroom sauce poured over a Swiss-topped beef patty: this is the coat-a-spoon texture to aim for in step 7, about 1/4 cup (50 to 60 ml) per burger. This is a homemade open-faced plate on toast with fries, not taken at Hardee’s. (Photo: jeffreyw, CC BY 2.0, https://commons.wikimedia.org/wiki/File:Mmm...Swiss\_cheese\_burger\_with\_mushrooms\_(5305019054).jpg (1600x1063, loading lazy). FLAG: needs an original 4-panel step photo grid of the copycat (patties chilling, sauce simmering, Swiss melting under a lid, sauce spooned over cheese))

Variant: the current Quarter Pound Mushroom & Swiss

To match the burger on hardees.com today, use a 113 g (4 oz) Angus patty on a toasted brioche-style bun and keep everything else the same. It belongs to the same Quarter Pound, brioche-style bun generation as our Hardee’s Big Cheeseburger copycat. For the Double, stack two 113 g patties with one slice of Swiss on the top patty and a little more sauce.

Why this copycat comes close to the original

This copycat follows the four parts Hardee’s names on its menu and cooks the beef the way the chain does: charbroiled.

• Charbroiled Angus beef. Hardee’s sells its patties as 100% Angus beef and lists the burger under ‘Charbroiled Burgers’. Grill marks and a little char carry most of the flavor.
• Salt and pepper only. A former employee quoted by Mashed said the patties are salted and peppered on site before going on the flame grill. That is a secondhand account, but it fits a burger this plain.
• Melted, not just sliced, Swiss. The menu says ‘melted Swiss’. Covering the patty for the last minute gives soft, draping cheese.
• A savory, beefy sauce. Beef broth and Worcestershire give a brown, savory sauce in the chain’s style without the canned soup. Hardee’s publishes no ingredient list, so this is the part of the copycat I’m least sure of.
• A toasted bun. The menu promises a ‘perfectly toasted’ bun, and toasting keeps the sauce from soaking through.

Hardee’s, Thickburgers and the mushroom-and-Swiss pairing

The Mushroom & Swiss comes from Hardee’s, a chain founded in 1960 in Greenville that had 1,492 US restaurants at the end of 2025, according to our Hardee’s brand profile. Hardee’s belongs to CKE Restaurants, which also owns Carl’s Jr. If you like this family of burgers, try our Carl’s Jr. Famous Star copycat or the Carl’s Jr. Western Bacon Cheeseburger copycat.

Mushrooms and Swiss have shown up in other Hardee’s burgers too. In 2009, the Portobello Mushroom Melt Thickburger paired a 1/3 lb charbroiled Black Angus patty with portobellos sautéed in garlic butter, caramelized onions and two slices of Swiss on sourdough. It had a suggested price of $3.79, or $5.79 as a combo, when Hardee’s had about 1,915 restaurants (Nation’s Restaurant News). It was a different burger, but it shows the pairing already had a place in the Thickburger line in 2009.

FAQ

What is on a Hardee’s Mushroom and Swiss?

As of November 12, 2026, Hardee’s lists a Quarter Pound 100% Angus beef patty, melted Swiss and mushroom sauce on a toasted brioche-style bun, at 580 calories. The Double has two Quarter Pound patties and 860 calories.

What is the difference between the Mushroom & Swiss Thickburger and today’s Mushroom & Swiss?

The Thickburger used a 1/3 lb patty. The current burger uses a Quarter Pound patty on a brioche-style bun and is sold under ‘Charbroiled Burgers’ without the Thickburger name. Hardee’s has not published when the change happened.

Should a Thickburger patty be 1/4 lb or 1/3 lb?

The Original Thickburger was 1/3 lb, about 151 g. The Little Thickburger was 1/4 lb and the Monster was 2/3 lb, according to Nation’s Restaurant News in 2008. I use 150 g for the 1/3 lb patty and 113 g for the Quarter Pound.

How do I make Hardee’s mushroom sauce at home?

Brown 150 g of sliced button mushrooms in 2 tbsp of butter, stir in 1 tbsp of flour, then simmer with 1/2 cup of beef broth, 1 tsp of Worcestershire and 1/4 tsp of onion powder for 3 to 4 minutes. That makes enough for two burgers.

Can I make the mushroom sauce ahead?

Yes. Cool it, keep it covered in the fridge for up to 2 days, and reheat it gently with a splash of broth to loosen it.

How do I get a charbroiled taste without a grill?

Use a cast-iron grill pan heated over high heat until it smokes lightly, and leave the patties alone so the ridges sear dark marks into them. Cook to 160°F (71°C) inside, as the USDA recommends for ground beef.

How many calories are in a Hardee’s Mushroom and Swiss?

Hardee’s lists 580 calories for the single and 860 for the double. I found no official figure for the old 1/3 lb Thickburger, and I did not calculate the calories of this copycat.

Did Hardee’s mushroom sauce come from Burger Chef?

That claim is unconfirmed. Hardee’s parent company Imasco bought Burger Chef in 1982 for $44 million and converted many of its restaurants to Hardee’s (Wikipedia), but no primary source links the mushroom sauce to Burger Chef.

Can I still order a Mushroom N’ Swiss Thickburger anywhere?

Possibly in the Middle East, where Hardee’s had more than 300 restaurants across Asia and the Middle East in 2016 (Wikipedia). The aggregator magicpin lists a ‘Mushroom N Swiss Thickburger’ on the menu of a Hardee’s in Mirdif, Dubai, but I could not check its patty weight or bun on an official regional site.

For more burger copycats, techniques and buns, browse the Burger Breton recipes hub.